In addition to the classic authors (ancient and modern), the following special works cited in the text may be con - sulted for details: Giovanni B. Antonelli, Sulla teoria mate - matica della economia politica (1866; Milan, 1952); M. Friedman and L. J.

In particular, the so-called “Formalist School,” starting under the leadership of the great German mathematician David Hilbert, adopted a symbolism obviously inspired by that of the Principia Mathe - matica.